How long/short have you bought/cut yours?
Any magic formulas that I'm not aware of?

The stock raiser one on my MTB were 615mm, now cut at 490mm or so, anything sorter and the brake lever would be in an angle

Got some nicer alloy Race face low rise bar and need to settle down on a lenght before cutting it

Edit: Corrected, should be 490 vs 510mm